In Dead or Alive 5, Muramasa watches over Kasumi at a hidden village in Japan. After Hayabusa's falcon delivers a message to summon her to battle, Kasumi thanks Muramasa for all that he has done for her while he encourages her to hurry and rescue Hayate.

Muramasa is an old man of medium-short height and usually bends forward when walking. His eyes are covered by his long white eyebrows, and he has a long white goatee growing from his chin. He usually wears shopkeeper attires with a bandana tied around his head.

Muramasa ia a kind old man who is ready to help Hayabusa in his times of need. Possessing plenty of supply for Hayabusa's disposal and having great knowledge of all that the ninja needs to know, Muramasa is an ally that Hayabusa can count on. Despite being very old, he can still wield a sword hidden within a cane and defeat his enemies with ease.

During Dead or Alive 5, Muramasa watches over Kasumi while her ninja brethren are fighting Donovan and his MIST organization. It's possible that this is a request from Hayabusa for Muramasa to watch over her. But whatever the reason, Muramasa takes care of Kasumi like she was his daughter.

Muramasa was been on the search for the Golden Scarab - a legendary and super rare artifact - for years. Only 50 of these are said to exist. Hayabusa can exchange a number of the artifacts for rare items with Muramasa.